1. Field of the Invention
The present invention relates to an endoscope system capable of taking measures against a plurality of electronic endoscopes provided with image pickup means different in specification from one other.
2. Description of the Related Art
In recent years, an electronic endoscope (referred also to as "an electronic scope" or referred simply as "a scope") which uses a solid state image pickup element such as a charge coupled device (hereinafter referred to as "a CCD") or the like, as an image pickup means has widely been used.
In such an electronic scope, observing parts also digress or ramify complicatedly, and it has been further found that a forward end portion of the endoscope is further reduced in diameter, in keeping with development of recent endoscope medical science. For example, for a thick organ part such as a large intestine or the like and for a thin organ part such as a trachea or the like, diameters of permitted or admitted endoscopes are different from one other. Accordingly, since the solid state image pickup element of a picture-element arrangement matched with the thick organ part is large in size, the endoscope for the thin organ cannot be arranged. Conversely, since the solid state image pickup element matched with the thin organ part is small in size with respect to the diameter of the endoscope for the thick organ, a surplus space is generated. This results in waste of a part which is originally an image pickup surface. This is not efficient. Accordingly, an endoscope having the picture-element arrangement taking measures against the observing parts has been required or necessitated.
In a conventional video camera or the like, for example, a picture element size or the number of longitudinal and lateral picture elements of the image pickup element is only a single type or kind, but there is no arrangement which uses image pickup elements equal to or more than two kinds. Further, also in the electronic scope, a, used solid state image pickup element has conventionally been limited to a single kind or type.
In an apparatus which uses the solid state image pickup element, in a case where specifications of the arranged solid state image pickup elements (the number of picture elements or the like, for example) are different from each other, driving of the solid state image pickup elements and signal processing of an output are required to be executed in accordance with the kinds or types of the respective solid state image pickup elements.
Nevertheless, since a drive circuit for the solid state image pickup element and a signal processing circuit are fixed, the conventional electronic endoscope apparatus has such a disadvantage that only an electronic scope can be used which uses the solid state image pickup elements which are the same in type as each other and the same in specification as each other.
In order to solve the above-discussed disadvantage or problem, there is an endoscope apparatus, for example, which has been proposed in Japanese Patent Laid-Open No. SHO 63-260527, in which a plurality of camera control units (CCU) taking measures respectively against electronic scopes different in kind from each other are prepared, and these plurality of camera control units are changeably mounted within a video process unit, whereby a different electronic scope can be used.
In a case of the endoscope apparatus disclosed in Japanese Patent Laid-Open No. SHO 63-260527, however, the existent endoscope apparatus, that is, the conventional endoscope apparatus in which the video process unit is such that the plurality of camera control units cannot be mounted exchangeably and cannot be adapted or adjusted. Moreover, since the camera control unit can be mounted exchangeably, there is a problem that the video process unit is enlarged in size.
Furthermore, U.S. Pat. No. 4,816,909 discloses an endoscope system in which, for the purpose of providing an electronic endoscope apparatus taking measures against a plurality of scopes which consist of solid state image pickup elements different in number of picture elements from each other, a detecting circuit for the scope is provided on a body apparatus, drive pulses of the solid state image pickup element and the signal processing circuit are switched to an adequate value by a detecting signal from the detecting circuit.
Since, however, the apparatus disclosed in U.S. Pat. No. 4,816,909 is so arranged as to take measures against an electronic scope which is different in number of picture elements of the solid state image pickup element from the first time, the arrangement of the signal processing circuit is complicated in structure. Further, there is such a disadvantage that a user must use the signal processing circuit provided with surplus functions, in a case also where the electronic endoscope apparatus is used only for a specific scope, for example.